The invention relates to a monitoring system with a pertinent hanging device for hanging of articles, especially works of art, which are provided with electrical security and/or illumination means. The invention furthermore relates to monitoring units for articles of this type.
A monitoring system of the generic type is known from the article xe2x80x9cProtecting Painting from Theftxe2x80x9d by J. R. Kaisley, Electrical Construction and Maintenance 76 (2/1977), page 62. This is an antitheft device for displayed paintings, on the wall behind the suspended paintings metal rails being attached which are electrically interconnected via three-wire cable to the corresponding connectors, each rail for each picture having a socket into which the three-pin connector can be inserted, in order to connect a miniswitch to the three-wire system of the rail by means of a three-wire cable. Each miniswitch is attached to the back of the frame of the painting by a wood screw and an adhesive surface. In this position the circuit is closed by the switch. Any movement on the frame of the painting breaks the switch away from the frame, by which the switch is moved by means of a pretensioning spring into a position in which the circuit is broken by the switch. The three-wire system of rails is connected to an alarm unit. As soon as the alarm unit acquires an interruption of the circuit, it triggers the corresponding theft alarm. It is not detailed how the paintings are hung.
The object of this invention is to devise a monitoring system and a pertinent hanging device for hanging articles which are to be put into electrical contact, which is characterized by especially simple handling and use and which allows hanging of articles as conveniently as possible.
Another object of the invention is to configure the pertinent hanging device for hanging articles to be put into electrical contact such that it is made economically, visually attractive and user-friendly.
Another object of the invention is to devise a monitoring unit for attachment to articles to be monitored, which is made simply and practically.
Another object of the invention is to devise a monitoring system for articles such that it is reliable and user-friendly and ensures a high security standard.
These objects are achieved by a monitoring system
The hanging device in accordance with the invention is very economical, visually attractive and user-friendly. The monitoring unit in accordance with the invention can be economically produced and is still reliable. The monitoring system in accordance with the invention with comfortable operation offers a high security standard and easily provides for good sensitivity.
In the following, first the hanging device provided in the monitoring system is presented. In accordance with one embodiment it is advantageous that only a single fastening unit is necessary for hanging the articles since it already has at least two current paths and thus is suited for complete, i.e. two-pole, contact-making. Furthermore it is advantageous that because the suspended fastening elements can move and the final suspension site for a certain article can be flexibly chosen with the fastening unit permanently installed.
The fastening elements can be made such that they ensure a selection option regarding to which of the current paths the contact or each contact establishes electrical contact. This allows standard formation of each fastening element so that only a uniform basic type of fastening element is necessary.
According to one alternative embodiment of the hanging device, there can be at least two types of fastening elements which differ by the arrangement of their contacts such that in the suspended state for each type of fastening element, at least one contact makes contact with another current path.
In a first embodiment of the fastening elements in accordance with the invention the selection option is ensured by the contact-making being dependent on the orientation in which the fastening element or each fastening element is suspended in the fastening unit. This eliminates any need to adjust the fastening element to the desired type of contact-making, but simply the orientation during suspension must be chosen accordingly. In this embodiment, the contacts are feasibly attached permanently to the fastening elements. In one preferred embodiment, each fastening element is made essentially mirror-symmetrically with reference to a center plane, there being two contact configurations between which it is possible to select by turning the orientation of the fastening element by 180xc2x0.
In a second embodiment of the fastening elements in accordance with the invention, the selection option is guaranteed by there being only one type of contact and by the fact that each contact before suspension of the fastening element can be used at different locations of the fastening element in order to determine the current path with which contact is to be made. In this case, the basic type of fastening element is adjusted before use to the desired contact configuration.
Alternatively, according to a third embodiment, the selection option can be achieved by there being at least two types of contacts and the contacts before suspension of the fastening element being inserted at a certain location of the fastening element, the choice of contact types determining the current path with which contact is to be made.
Alternatively, according to a fourth embodiment, the selection option can be achieved by there being only a single type of fastening unit, a single type of contact and only a single type of fastening element, and contact can be made as desired by specific location of the contact and fastening element on the fastening unit.
The fastening unit is preferably made rail-like, and it can comprise a profile part which partially encompasses an interior and each current path is made as a busbar which is applied to the profile part in the interior, the profile part being made preferably to be electrically insulating. The contacts are preferably made as brush springs.
The profile part in a first embodiment is preferably made channel-shaped with three essentially closed sides and with one side which has been provided with a through, elongated opening, the fastening elements having the capacity to be suspended by means of the opening in the profile part.
Alternatively, the profile part can be made channel-shaped with three sides, it being attachable by its back to one wall, the front being essentially open and the top being provided with a first slot and the bottom being provided with a second slot, and the fastening elements with their top end can be suspended in the first slot and can be engaged in the second slot by their bottom end.
Preferably, there are diaphragm parts which can be inserted into the opening or the open side of the profile part and which are provided preferably with contacts to make contact with the current paths and with electronic means which are conductively connected to these contacts.
Alternatively to the rail-like configuration of the fastening unit, the contacts can be made such that they are used to suspend the fastening elements in the fastening unit. In doing so, the fastening unit preferably comprises several holding elements which are to be attached stationary in a row and at least two parallel tubular or rod-shaped current leads, the current leads being held by the holding elements. The contacts are made such that they can be suspended in one of the current leads. Preferably, for each contact there is a correspondingly made insulated auxiliary element which can be suspended in one of the current leads. In this embodiment, the selection option of the contact configuration is achieved by the contact configuration depending on the orientation of the fastening element during suspension.
Preferably, each fastening element has an eye for suspending a hanging element which is connected to the article to be hung and which is conductively connected to the contact or to each contact. The hanging elements are preferably made as electrically conductive cables or chains. The articles to be hung are preferably works of art which are provided with electrical security and/or illumination means. The current paths are connected to a power source and/or a control unit in order to establish electrical contact between the power source and/or the control unit and the corresponding security and/or illumination means on the works of art via the hanging device.